This invention relates to data transmission systems that are used to transmit broadband data and in particular, to a system for converting the format of clear channel payloads in a manner to minimize conversion delays yet comply with the industry standard formatting requirements.
It is a problem in data transmission systems to efficiently convert data between different data formats. The need for data format conversion arises when the data transmission network is connected to terminal equipment which uses a data format that differs from the one used by the data transmission network. Typical data transmission systems frequently use custom integrated circuits to perform the data format conversion, but these circuits are expensive to develop and cannot be changed as the data formats change over time. An alternative to the use of custom integrated circuits is the use of software systems, but these systems trade speed of data format conversion provided by the custom integrated circuits for the flexibility to adapt to changes in the data format. Thus, it is a problem to implement data format conversion systems that are time wise efficient, inexpensive, and easy to modify to reflect changes in data formats.
In the case of AUG/AU3/VC3 clear channel payloads and AU4/VC4/TU3/VC3 clear channel payloads, a standard ITU conversion technique is used, which incurs a full frame of delay to effect the format conversion. Thus, each time the data stream must be converted to accommodate the needs of a particular circuit, this delay is added to the signal path, thereby reducing the effective data throughput of the overall system due to the signal processing delays and the need to process complex format conversion algorithms. The conversion of these clear channel payloads is presently effected by the use of custom integrated circuits which are expensive to develop and cannot be changed as the data formats change over time.
The above described problems are solved and a technical advance achieved by the present system for broadband data payload conversion that functions to efficiently convert broadband data between two sets of data formats. In particular, this software system converts between AUG/AU3/VC3 clear channel payloads and AU4/VC4/TU3/VC3 clear channel payloads in an efficient manner, which also complies with the industry standard data formatting requirements. The present system implements an efficient data format conversion process that uses existing circuitry and can effect the data format conversion with only a few bytes of delay instead of an entire frame of delay as is typically found in existing systems. This is accomplished by manipulating the format conversion to simplify the format conversion process.